Light sensitive digitizer system

ABSTRACT

A digitizer sensor includes a plurality of antennas defining a grid of junctions and light sensitive material configured to affect capacitive coupling at one or more junctions based on exposure to a beam projected on the digitizer sensor. The plurality of antennas of the digitizer sensor is configured to sense capacitive coupling at the junctions.

RELATED APPLICATION

This application claims the benefit of priority under 35 USC §119(e) ofU.S. Provisional Patent Application No. 62/080,341 filed on Nov. 16,2014, the contents of which are incorporated herein by reference intheir entirety.

BACKGROUND

Digitizing systems that allow a user to operate a computing device atclose range with a stylus and/or finger are known. Typically, adigitizer system includes a digitizer sensor that is integrated with adisplay screen, e.g., over-laid on the display screen of the computingdevices. The detected position of the stylus and/or conductive object,such as a finger or another body part, provides input to the computingdevice associated with the display, and is interpreted by the computingdevice as user commands. Input is detected while the stylus and/orconductive object is touching or hovering over the digitizer sensor.Some styluses provide input by transmitting a signal that is picked upby the digitizer sensor at a location proximal to a writing tip of thestylus. Examples of computing devices with digitizer systems includetablets, pen enabled laptop computers, or hand held device such assmart-phones.

Some digitizer systems operate with a capacitive based digitizer sensor.Capacitive based digitizer sensors include electrodes that can beconstructed from different media, such as copper, Indium Tin Oxide (ITO)and printed ink. ITO is typically used to achieve transparency. Somecapacitive based digitizer sensors are grid based and are operated todetect mutual capacitance between the electrodes at different points inthe grid.

SUMMARY

According to an aspect of some embodiments of the present disclosurethere is provided a capacitive based digitizer sensor that can detect atrack beam of light projected on the sensor, e.g. infrared (IR)radiation. Optionally, the beam is projected from a distance of up to afew meters from the digitizer sensor, e.g. with a remote control orlaser pointer. In one example, a laser pointer can select and movevirtual objects displayed on a touch enabled screen from a distance.Alternatively, the beam may be projected at close range, e.g. with astylus interacting with the digitizer sensor by hover and touch. Thesame digitizer sensor is also sensitive to finger touch input, to inputby objects having conductive or dielectric properties as well as inputfrom a stylus that emits a signal.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art. Although methods and materials similar or equivalentto those described herein can be used in the practice or testing ofembodiments of the disclosure, exemplary methods and/or materials aredescribed below. In case of conflict, the patent specification,including definitions, will control. In addition, the materials,methods, and examples are illustrative only and are not intended to benecessarily limiting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments of the disclosure are herein described, by way ofexample only, with reference to the accompanying drawings. With specificreference now to the drawings in detail, it is stressed that theparticulars shown are by way of example and for purposes of illustrativediscussion of embodiments of the disclosure. In this regard, thedescription taken with the drawings makes apparent to those skilled inthe art how embodiments of the disclosure may be practiced.

In the drawings:

FIG. 1 is a simplified schematic drawing of a touch-screen in accordancewith some embodiments of the present disclosure;

FIG. 2 is a simplified schematic drawing of a digitizer sensor includinglight sensitive material at junction areas between row and columnconductive strips in accordance with some embodiments of the presentdisclosure;

FIG. 3 is a simplified schematic drawing of a digitizer sensor includinga layer of light sensitive material in accordance with some embodimentsof the present disclosure;

FIGS. 4A and 4B are simplified schematic drawings of a digitizer sensorincluding light sensitive material applied under bridges of thedigitizer sensor and a detailed blow up of a bridge area respectively inaccordance with some embodiments of the present disclosure;

FIGS. 5A and 5B are simplified schematic cross sections cut along acolumn and a row direction respectively of a double layer digitizersensor in accordance with to some exemplary embodiments of the presentdisclosure;

FIGS. 6A, 6B, 6C, 6D, 6E and 6F are simplified schematic drawings ofexemplary sensor stack in accordance with some embodiments of thepresent disclosure;

FIG. 7 is simplified schematic drawing of exemplary devices forprojecting a beam that can be tracked by a digitizer sensor inaccordance with some exemplary embodiments of the present disclosure;

FIGS. 8A and 8B are graphs of exemplary modulated light signal imposedon a digitizer sensor and corresponding output detected in accordancewith some embodiments of the present disclosure; and

FIG. 9 is a simplified schematic drawing of a touch enabled computingdevice in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

According to some embodiments of the present disclosure, light sensitivematerial is integrated into a capacitive based digitizer sensor. Thelight sensitive material is configured to alter capacitive couplingbetween sensing elements of a capacitive based digitizer sensor at alocation(s) that is radiated. The light sensitive material mayalternatively be configured to alter resistance of a resistive-baseddigitizer or may introduce a resistive path to a capacitive baseddigitizer sensor. Typically, the sensitivity of the material is for adefined range of wavelengths, e.g. IR range that can be distinguishedfrom ambient light.

Typically, the change in capacitive coupling or resistance that occursin response to light exposure is detected by circuitry associated withthe digitizer sensor. In some exemplary embodiments, output detected inresponse to light exposure is differentiated from output detected fromother interaction, e.g. finger touch interaction and conductive objectinteraction. In some exemplary embodiments, the input provided by thelight source is encoded and the circuitry associated with the digitizersensor decodes information encoded.

The light sensitive material may be a photoconductive material thatalters resistivity when exposed or photovoltaic material that generatesa potential when exposed. Optionally, a photodiode is used to sense beamprojected on the digitizer sensor. In some exemplary embodiments, thelight sensitive material is transparent.

The light sensitive material can be applied as a layer covering thedigitizer sensor or can be dispersed around the sensor, e.g. positionedin junction areas of a grid based capacitive sensor. Differentconfigurations can be applied for integrating the light sensitivematerial with a digitizer sensor formed on a single layer, a digitizersensor including ITO on a single layer and bridges and a digitizersensor including two sensing layers, e.g. a separate row layer andcolumn layer.

In some exemplary embodiments, photovoltaic material is integrated onthe digitizer sensor for accumulating charge for powering the computingdevice with the digitizer sensor. Optionally, the light sensitivematerial applied for accumulating charge for powering the computingdevice is selected to be sensitive to ambient light and is other oradded in addition to light sensitive material applied to detectinteraction based on radiation input.

Exemplary light sensitive material that may be applied includes Leadsulfide (PbS), Lead selenide (PbSe), Indium antimonide (InSb), Mercurycadmium telluride (MCT,HgCdTe), Mercury zinc telluride (MZT, HgZnTe),Mercury cadmium telluride (MCT,HgCdTe), Indium antimonide (InSb),Cadmium sulphide (CdS), Indium antimonide (InSb), Indium galliumarsenide (InGaAs), Germanium, Indium arsenide (InAs), Platinum silicide(PtSi), or other material. Transparency of the material may be achievedby using carbon nanotube technology with quantum dots. In some exemplaryembodiments, the response time for the photoconductive material mayrange between 0.2 msec to 10 msec, while the response times for thephotovotalic or photodiode material is typically shorter.

Before explaining at least one embodiment of the exemplary embodimentsin detail, it is to be understood that the disclosure is not necessarilylimited in its application to the details of construction and thearrangement of the components and/or methods set forth in the followingdescription and/or illustrated in the drawings and/or the Examples. Thedisclosure is capable of other embodiments or of being practiced orcarried out in various ways.

Reference is now made to FIG. 1 showing a simplified schematic drawingof a touch-screen in accordance with some embodiments of the presentdisclosure. Typically, a touch-screen 10 includes a digitizer sensor 60integrated on a display 45. The digitizer may be integrated with display45 by bonding the digitizer onto a display stack, or by using out cell,on cell, or in cell digitizer technologies in which to the digitizingelements shared circuits within display 45. Display 45 is typically aflat panel display (FPD) used in laptop computers, tables, smart-phones,monitors for personal computers and television screens. Digitizer sensor60 is typically a grid based capacitive sensor that is integrated withlight sensitive material.

According to some exemplary embodiments, a touch-screen 10 detects andtracks touch and hover of a fingertip 46, a signal emitting stylus 200and also a beam 100 projected by a beam generator 150 on touch-screen10. Stylus 200 typically emits a signal in the form of an electric fieldfrom its writing tip. Typically, input from finger 46 and stylus 200 islimited to detection at close range, e.g. up to a distance of 30 mm or50 mm from touch-screen 10 while input from beam generator 150 can bedetected at both a close range and a far range. Optionally, a beam 100emitted by beam generator 150 can be detected from a distance of up to 1meter, up to 5 meters or up to 10 meters or more from touch-screen 10.

Typically, digitizer sensor 60 with associated circuitry cansimultaneously detect and track position of input received fromfingertip 45, stylus 200 and beam 100. Optionally, a cursor or marker onscreen 45 follows a detected location of beam 100. In some exemplaryembodiments, digitizer sensor 60 can also detect information encoded onthe signal emitted by stylus 200 or on beam 100. Optionally, beamgenerator 150 includes a user selected button 155 that can apply amodulation that emulates mouse selection function or other function.Optionally, the modulation is used for data transfer from beam generator150 to the digitizer sensor 60.

In some exemplary embodiments, beam generator 150 includes a low powerlaser diode that emits coherent light in the IR range, e.g. 800 nm-3000nm wavelength. Optionally, beam generator 150 additionally includesdiode emitting in a visible range that can be detected by a user lookingthat the touch-screen. Optionally, beam generator 150 emits light in thevisible range and the visible range is tracked with the digitizersensor. Typically, on the fly calibration is applied when tracking lightin the visible range to differentiate between dose energy received frombeam generator 150 and ambient light energy. Beam generator 150 may beincluded in a laser pointer, a remote control used to operate atelevision screen or a stylus. Optionally, beam generator 150 can beintegrated with stylus 200. Optionally, beam generator 150 radiates abeam from a tail end of stylus 200 opposite the end including thewriting tip.

Reference is now made to FIG. 2 showing a simplified schematic drawingof a digitizer sensor including light sensitive material at junctionareas between row and column conductive strips in accordance with someembodiments of the present disclosure. In some exemplary embodiments,digitizer sensor 61 is a double layer sensor that includes a firstsubstrate patterned with row antennas 20 overlaid on a second substrateincluding column antennas 30. Row antennas 20 and column antennas 30cross to form a grid of junctions 25. Typically, row antennas 20 andcolumn antennas 30 are electrically insulated from one another and eachof the antennas is connected at least at on one end to digitizercircuitry. According to some embodiments of the present disclosure,light sensitive material 50 is patterned in junction areas 25 betweenrow antennas 20 and column antennas 30. Optionally, light sensitivematerial 50 is a photoconductive material that changes its resistivitywhen radiated by a defined wavelength. Optionally, material 50 issensitive to wavelength in the IR range between 850 nm to 1500 nm.Alternatively, material 50 is a photovoltaic material that generates apotential when exposed to light at a defined wavelength. Preferably,material 50 is transparent. Optionally, material 50 provides theelectrical insulation between the row and column antennas.

A conductive property of material 50 changes when a beam is projected onone or more junctions 25 and the change affects the coupling at thejunction(s) that are radiated. Changes in coupling in response tochanges in conductive property of material 50 can be detected whenapplying mutual capacitance detection or self capacitance detectionmethods. In some exemplary embodiments, material 50 creates a short at ajunction that is radiated.

Reference is now made to FIG. 3 showing a simplified schematic drawingof a digitizer sensor including a layer of light sensitive material inaccordance with some embodiments of the present disclosure. In someexemplary embodiments, digitizer sensor 62 can be any one of a doublelayer sensor, a single layer sensor or a single layer sensor with bridgeelements. According to some embodiments of the present disclosure, lightsensitive material 52 is a continuous layer disposed across digitizersensor 62. Material 52 may be applied on a surface of sensor 62 thatfaces display 45, may be applied between a layer including row antennas20 and a layer including column antennas 30 or may be applied on asurface of sensor 62 that faces a user interaction surface. Preferably,material 52 is transparent so that it does not substantially obstructdisplay 45. Optionally, a mesh printing process is used to improvetransparency of the layer.

According to some exemplary embodiments, a conductive property ofmaterial 52 changes locally in response to projected radiation. Thechange in the conductive property can alter coupling at junctions 25radiated and can alter coupling between display 45 and sensor 62 in thearea that is radiated. Typically, local changes in the conductiveproperty of material 52 can be detected during mutual or self capacitivedetection.

In some exemplary embodiments, light sensitive material 52 is aphotoconductive material that changes its resistivity when radiated by adefined wavelength. Optionally, material 52 is sensitive to wavelengthin the IR range between 850 nm to 1500 nm. Alternatively, material 52 isa photovoltaic material that generates a potential when radiated.

In some exemplary embodiments, material 52 is a photovoltaic materialthat is operated to accumulate charge for powering a touch enableddevice as opposed to tracking location of a beam. In such embodiments,material 52 may be selected to be sensitive to a visible range, e.g. 400nm to 800 nm that may typically be projected over the entire sensor 62.Any changes in capacitive coupling will typically effect the entiresensor so that the radiation detected will not be confused withinteraction and a discrete location.

Reference is now made to FIGS. 4A and 4B showing simplified schematicdrawings of a digitizer sensor including light sensitive materialapplied under bridges of the digitizer sensor and a detailed blow up ofa bridge area respectively in accordance with some embodiments of thepresent disclosure. According to some exemplary embodiments, a digitizersensor 64 is a sensor with a single ITO layer with bridges 35 (shown inblowup 80) that connect segments of column antennas 30 over row antennas20 at junction areas 25. Typically, in known single layer sensors withbridges, non-conductive material is applied under bridges 35 to provideelectrical insulation between row and column antennas at junctions 25.In some exemplary embodiments, light sensitive material 54 is used inplace of the insulation that is typically used and material 54 isapplied under and optionally around bridges 35.

In some exemplary embodiments, light sensitive material 54 is nottransparent to but is small enough so that it does not significantlyimpair visibility of display 45. In some exemplary embodiments, for abridge dimension of 10 μm×200 μm, material 54 may have dimensions 200μm×200 μm and a thickness or height of 0.2-3 μm or 1-3 μm.

Light sensitive material 54 may be a photoconductive material orphotodiode material as discussed herein above. In some exemplaryembodiments, when one or more junctions 25 are radiated with a beamhaving a defined wavelength, a change in a conductive property ofmaterial 54 occurs and the change affects the capacitive coupling at thejunction(s) that are radiated.

Reference is now made to FIGS. 5A and 5B showing simplified schematiccross sections cut along a column and a row direction respectively of adouble layer digitizer sensor in accordance with some exemplaryembodiments of the present disclosure. In some exemplary embodiments, adigitizer sensor 66 includes light sensitive material 56 patternedbetween pairs of row antennas 20 (and pairs of column antennas 30). Insome exemplary embodiments, projection of beam on material 56 increasesthe coupling between parallel antennas 20. Optionally, a short iscreated between parallel antennas 20 while the beam is projected onmaterial 56. Mutual or self capacitive detection can be applied todetect output on antennas that are contiguous to antennas that are beingtriggered.

Reference is now made to FIGS. 6A, 6B, 6C, 6D, 6E and 6F showingsimplified schematic drawings of exemplary sensor stack in accordancewith some embodiments of the present disclosure. According to someexemplary embodiments, a digitizer sensor 60 includes a stackup oflayers with light sensitive material 50 integrated as one of the layersin the stackup. Exemplary stackups for single layer ITO sensor withbridges 35 (FIG. 4B) is shown in FIGS. 6A-6D. The stackup typicallyincludes a glass/film substrate 305 over which a user interacts, a ITOlayer 310, a isolator layer 315 patterned in junction areas, a metallayer 320 including a pattern of bridges 35 (FIG. 4B) and a passivationlayer 325. Passivation layer 325 is typically the layer that is overlaidon digitizer electrodes or antennas (for electrical and mechanicalprotection).

In some exemplary embodiments, a layer of light sensitive material 54for sensing interaction with a beam generator is used in place ofisolator layer 315 as discussed in reference to FIGS. 4A and 4B.Alternatively, a continuous layer of to material 52 is used in place ofpassivation layer 325 (FIG. 6B) and activation of material 52 locallyincreases capacitive coupling between antennas (mutual capacitance). Inanother exemplary embodiment, material 52 is added between glass/filmsubstrate 305 and ITO layer 310 (FIG. 6C). Another option is to applylight sensitive material 52 on a surface of passivation layer 325 thatfaces the display 45.

A stackup including light sensitive material for an exemplary singlelayer ITO sensor that does not include bridges 35 may be similar to thestackup shown in FIGS. 6A-6D but without the metal layer. For singlelayer digitizer sensors that do not include bridges, light sensitivematerial 52 can be integrated as a continuous layer between the ITOlayer 310 and passivation layer 325 (FIG. 6A), in place of thepassivation layer 325 (FIG. 6B), between glass/film substrate 305 andITO layer 310 (FIG. 6C), or under passivation layer 325 (FIG. 6D). Fordouble layer digitizer sensors shown in FIGS. 6E and 6F, the lightsensitive material 50 may be integrated between ITO layers 335 and 340(FIG. 6E) as shown for example in FIG. 2 or between an optically clearadhesive (OCA) film 330 and a top ITO layer 335 (FIG. 6F). Typically, aseparation layer 345 is included between ITO layers 335 and 340.

Reference is now made to FIG. 7 showing simplified schematic drawings ofexemplary devices that project a beam that can be tracked by a digitizersensor in accordance with some exemplary embodiments of the presentdisclosure. Devices 150 and 152 are exemplary devices that are shaped asa stylus and emit a beam 100 from one end of the stylus. Devices 150 maybe configured for close range detection, e.g. 0-30 mm from the digitizersensor or far range detection, e.g. 10 cm-5 m from the digitizer sensor.Typically, shape and power of beam 100 is defined based on the expecteddistance of interaction and the resolution desired.

Device 152 is an exemplary stylus that emits a signal such as anelectric field from one tip 157, e.g. the writing tip of the stylus andradiates a beam of light at a defined wavelength from a tip 158 at anopposite end. Optionally tip 158 can be used to add functionality to aconventional stylus. Optionally, tip 158 can provide erasingfunctionality or can be configured for remote interaction with atouch-screen, e.g. at distances of 10 cm-1 m.

In some exemplary embodiments, when photoconductive material is used toto track beam 100, parameters of beam 100 are defined based on thefollowing relationship:

ΔR=α·PT·AT/AD  Equation (1)

Where:

ΔR is the change in resistance in response to exposure to beam 100;

α is the responsivity of the photoconductive material, e.g. α=7×1010Ω/W;

PT is the power output of device 150 (or device 152) emitting beam 100,e.g. PT=0.5-1 mW;

AT is the light emitter opening area with diameter of the beam emittedfrom device 150 (or device 152), e.g. 0.4 mm; and

AD is beam spot area detected when spot diameter of beam 100 projectedon the photoconductive material, e.g. 7 mm.

In one exemplary embodiments, when the power output of device 150 isselected to be 0.5 mW and diameter of beam 100 is emitted from anaperture with diameter 0.4 mm, a change in resistance of thephotoconductive material will be (7×1010) (0.5×10-3)(π(0.2×10-3)2)/AD=4.4/AD. AD typically depends on the distance betweendevice 150 and the photoconductive material. In one exemplaryembodiments, when the beam spot has a diameter is 7 mm, ΔR=114K Ω. Ifthe initial resistance of the photoconductive material is for example 1M Ω, R=114 K Ω provides 11.5% change resistance due to exposure.

In other exemplary embodiments, when a beam 100 is configured to bedetected by a photodiode material, parameters of beam 100 are definedbased on the following relationship:

I=ρ·PT·AT/AD  Equation (2)

Where:

I is the current output in Amps; and

ρ is the responsivity of the photodiode material, e.g. 0.7 A/W.

In an exemplary embodiments, when the power output of device 150 isselected to be 0.5 mW and diameter of beam 100 is emitted from anaperture with diameter 0.4 mm, current, I generated by the photodiodematerial will be (0.7) (0.5×10-3) (π(0.2×10-3) 2)/AD=4.4×10-11/AD. Inone exemplary embodiments, when AD diameter is 7 mm, I=1.14 μA, which isalso significant signal (10-15% to change).

Optionally, devices 150 and 152 include one or more user operatedbuttons 155 that can be selected to impose a modulation of beam 100 thatcan be detected by the digitizer sensor. Optionally, beam 100 is apulsed beam that pulses a defined frequency and modulation of beam 100is based on ON/OFF pulsing of the beam.

Reference is now made to FIGS. 8A and 8B showing simplified graphs ofexemplary modulated beam signal imposed on a digitizer sensor andcorresponding output detected in accordance with some embodiments of thepresent disclosure. According to some embodiments of the presentdisclosure, beam 100 is pulsed at a pre-defined rate and binary encodingof beam 100 can be imposed by ON/OFF pulsing as shown in FIG. 8Aproviding an exemplary response shown in FIG. 8B. Typically, outputshown in FIG. 8B depends on parameters of the light sensitive material,e.g. response time of the material.

Reference is now made to FIG. 9 showing a simplified schematic drawingof a touch enabled computing device in accordance with some embodimentsof the present disclosure. According to some embodiments of the presentdisclosure, a touch enabled computing device 300 includes digitizersensor 360 integrated with display 45 (together a touch-screen), adigitizer controller 225 and a host computer 222. Digitizer sensor 360is a typically a grid based digitizer sensor including row antennas 20and column antennas 30 arranged to form a grid of junctions. Rowantennas 20 and column antennas 30 are typically connected to controller225. Controller 225 operates to trigger antennas for mutual capacitiveor self capacitive detection, to sample output from row and columnantennas and to process the output sampled. Typically, controller 225reports interaction coordinates to host 222.

Optionally, additional information is reported to host 222. Typically,controller 225 detects and tracks coordinates of input from one or morefingers, from a signal emitting stylus and from a beam generatorprojecting a beam on digitizer sensor 360. In some exemplaryembodiments, controller 225 also demodulates information included withthe beam generator or on the signal emitted from the stylus.

According to exemplary embodiments, digitizer sensor 360 includes lightsensitive material 50 that is configured locally change couplingcharacteristics of digitizer sensor 360 at locations exposed toradiation. Light sensitive material 50 can be dispersed in discreteareas over sensor 360 or may be a continuous layer extending to oversensor 360. Typically, exposure to a defined wavelength increasescapacitive coupling in the area of exposure. Optionally, a short iscreated between coupled elements of sensor 360 in the area of exposure.Typically, light sensitive material 50 is not connected to controller225 but rather its affect is detected from output sampled on theantennas.

In some exemplary embodiments, digitizer sensor 360 includes additionallight sensitive material 59 that is connected to controller 225.Optionally, light sensitive material 59 is formed from photovoltaic orphotodiode material that generates charge when exposed to radiation.Typically, material 59 is also sensitive to a visible range ofwavelengths. In some exemplary embodiments, the generated charge is usedto power computing device 300.

According to an aspect of some embodiments there is provided a digitizersensor including a plurality of antennas defining a grid of junctions,wherein the plurality of antennas are configured to sense capacitivecoupling at the junctions; and light sensitive material configured toaffect capacitive coupling at one or more junctions based on exposure toa beam projected on the digitizer sensor.

Optionally, the light sensitive material is a photo conductive material.

Optionally, the light sensitive material is a photovoltaic material or aphotodiode material.

Optionally, the light sensitive material is transparent.

Optionally, the light sensitive material is disposed based on a meshprinting process.

Optionally, the light sensitive material disposed at the junctions.

Optionally, the light sensitive material is a continuous layer across asurface of the digitizer sensor.

Optionally, the sensor includes an ITO layer and a protective layerdefining a user interaction surface, wherein the light sensitivematerial is disposed between an ITO layer and the protective layer.

Optionally, the sensor includes an ITO layer and a protective layerdefining a user interaction surface, wherein the protective layer isdisposed over the ITO layer and the light sensitive material is disposedunder the ITO.

Optionally, the plurality of antennas includes an array of parallelantennas and to wherein the light sensitive material is disposed betweenparallel antennas of the array.

Optionally, the plurality of antennas includes an array of row antennasand an array of column antennas and wherein the light sensitive materialis disposed between pairs the row and the column antennas.

Optionally, the light sensitive material is configured create a shortbetween antennas of the plurality that are exposed to the beamprojected.

Optionally, the light sensitive material is sensitive to wavelengthsbetween 800-3000 nm.

Optionally, the light sensitive material is configured to respond to thebeam projected from a distance of between 0-10 m.

Optionally, the response time of the light sensitive material is between0.2 msec-10 msec.

According to an aspect of some embodiments there is provided digitizersensor including a plurality of antennas defining a grid of junctions,wherein the plurality of antennas are configured to sense capacitivecoupling at the junctions; light sensitive material configured to affectoutput detected at one or more junctions based on exposure to a beamprojected on the digitizer sensor; and a circuit configured to sampleoutput from the plurality of antennas and to detect location of the beamon the digitizer sensor based on output.

Optionally, the light sensitive material is configured to affect acapacitive or resistive path between antennas at one or more junctionsbased on the exposure to the beam projected on the digitizer sensor.

Optionally, the circuit samples output based on a mutual capacitivedetection method.

Optionally, the light sensitive material is photovoltaic material thataccumulates charge based on exposure to a beam projected on thedigitizer sensor and wherein the circuit is configured to power thedigitizer system with the charge.

Optionally, the circuit is configured to simultaneously track one ormore fingers touching the digitizer sensor and one or more beamsprojected on the digitizer sensor.

Optionally, the circuit configured to detect and decode modulationsimposed on the beam.

Certain features of the examples described herein, which are, forclarity, to described in the context of separate embodiments, may alsobe provided in combination in a single embodiment. Conversely, variousfeatures of the examples described herein, which are, for brevity,described in the context of a single embodiment, may also be providedseparately or in any suitable sub-combination or as suitable in anyother described embodiment of the disclosure. Certain features describedin the context of various embodiments are not to be considered essentialfeatures of those embodiments, unless the embodiment is inoperativewithout those elements.

What is claimed is:
 1. A digitizer sensor comprising: a plurality ofantennas defining a grid of junctions, wherein the plurality of antennasare configured to sense capacitive coupling at the junctions; and lightsensitive material configured to affect capacitive coupling at one ormore junctions based on exposure to a beam projected on the digitizersensor.
 2. The digitizer sensor of claim 1, wherein the light sensitivematerial is a photo conductive material.
 3. The digitizer sensor ofclaim 1, wherein the light sensitive material is a photovoltaic materialor a photodiode material.
 4. The digitizer sensor of claim 1, whereinthe light sensitive material is transparent.
 5. The digitizer sensor ofclaim 1, wherein the light sensitive material is disposed based on amesh printing process.
 6. The digitizer sensor of claim 1, wherein thelight sensitive material disposed at the junctions.
 7. The digitizersensor of claim 1, wherein the light sensitive material is a continuouslayer across a surface of the digitizer sensor.
 8. The digitizer sensorof claim 1, comprising an Indium Tin Oxide (ITO) layer and a protectivelayer defining a user interaction surface, wherein the light sensitivematerial is disposed between an ITO layer and the protective layer. 9.The digitizer sensor of claim 1, comprising an ITO layer and aprotective layer defining a user interaction surface, wherein theprotective layer is disposed over the ITO layer and the light sensitivematerial is disposed under the ITO.
 10. The digitizer sensor of claim 1,wherein the plurality of antennas includes an array of parallel antennasand wherein the light sensitive material is disposed between parallelantennas of the array.
 11. The digitizer sensor of claim 1, wherein theplurality of antennas includes an array of row antennas and an array ofcolumn antennas and wherein the light sensitive material is disposedbetween pairs the row and the column antennas.
 12. The digitizer sensorof claim 1, wherein the light sensitive material is configured create ashort between antennas of the plurality that are exposed to the beamprojected.
 13. The digitizer sensor of claim 1, wherein the lightsensitive material is sensitive to wavelengths between 800-3000 nm. 14.The digitizer sensor of claim 1, wherein the light sensitive material isconfigured to respond to the beam projected from a distance of between0-10 m.
 15. The digitizer sensor of claim 1, wherein the response timeof the light sensitive material is between 0.2 msec-10 msec.
 16. Adigitizer sensor comprising: a plurality of antennas defining a grid ofjunctions, wherein the plurality of antennas are configured to sensecapacitive coupling at the junctions; light sensitive materialconfigured to affect output detected at one or more junctions based onexposure to a beam projected on the digitizer sensor; and a circuitconfigured to sample output from the plurality of antennas and to detectlocation of the beam on the digitizer sensor based on output.
 17. Thedigitizer sensor of claim 16, wherein the light sensitive material isconfigured to affect a capacitive or resistive path between antennas atone or more junctions based on the exposure to the beam projected on thedigitizer sensor.
 18. The digitizer system of claim 16, wherein thecircuit samples output based on a mutual capacitive detection method.19. The digitizer system of claim 16, wherein the light sensitivematerial is photovoltaic material that accumulates charge based onexposure to a beam projected on the digitizer sensor and wherein thecircuit is configured to power the digitizer system with the charge. 20.The digitizer system of claim 16, wherein the circuit is configured tosimultaneously track one or more fingers touching the digitizer sensorand one or more beams projected on the digitizer sensor.
 21. Thedigitizer system of claim 16, wherein the circuit configured to detectand decode modulations imposed on the beam.